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13#include <linux/module.h>
14#include <linux/skbuff.h>
15#include <linux/route.h>
16#include <linux/netfilter/x_tables.h>
17#include <net/route.h>
18#include <net/netfilter/ipv4/nf_dup_ipv4.h>
19#include <net/netfilter/ipv6/nf_dup_ipv6.h>
20#include <linux/netfilter/xt_TEE.h>
21
22struct xt_tee_priv {
23 struct list_head list;
24 struct xt_tee_tginfo *tginfo;
25 int oif;
26};
27
28static const union nf_inet_addr tee_zero_address;
29
30static unsigned int
31tee_tg4(struct sk_buff *skb, const struct xt_action_param *par)
32{
33 const struct xt_tee_tginfo *info = par->targinfo;
34 int oif = info->priv ? info->priv->oif : 0;
35
36 nf_dup_ipv4(xt_net(par), skb, xt_hooknum(par), &info->gw.in, oif);
37
38 return XT_CONTINUE;
39}
40
41#if IS_ENABLED(CONFIG_IPV6)
42static unsigned int
43tee_tg6(struct sk_buff *skb, const struct xt_action_param *par)
44{
45 const struct xt_tee_tginfo *info = par->targinfo;
46 int oif = info->priv ? info->priv->oif : 0;
47
48 nf_dup_ipv6(xt_net(par), skb, xt_hooknum(par), &info->gw.in6, oif);
49
50 return XT_CONTINUE;
51}
52#endif
53
54static DEFINE_MUTEX(priv_list_mutex);
55static LIST_HEAD(priv_list);
56
57static int tee_netdev_event(struct notifier_block *this, unsigned long event,
58 void *ptr)
59{
60 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
61 struct xt_tee_priv *priv;
62
63 mutex_lock(&priv_list_mutex);
64 list_for_each_entry(priv, &priv_list, list) {
65 switch (event) {
66 case NETDEV_REGISTER:
67 if (!strcmp(dev->name, priv->tginfo->oif))
68 priv->oif = dev->ifindex;
69 break;
70 case NETDEV_UNREGISTER:
71 if (dev->ifindex == priv->oif)
72 priv->oif = -1;
73 break;
74 case NETDEV_CHANGENAME:
75 if (!strcmp(dev->name, priv->tginfo->oif))
76 priv->oif = dev->ifindex;
77 else if (dev->ifindex == priv->oif)
78 priv->oif = -1;
79 break;
80 }
81 }
82 mutex_unlock(&priv_list_mutex);
83
84 return NOTIFY_DONE;
85}
86
87static int tee_tg_check(const struct xt_tgchk_param *par)
88{
89 struct xt_tee_tginfo *info = par->targinfo;
90 struct xt_tee_priv *priv;
91
92
93 if (memcmp(&info->gw, &tee_zero_address,
94 sizeof(tee_zero_address)) == 0)
95 return -EINVAL;
96
97 if (info->oif[0]) {
98 if (info->oif[sizeof(info->oif)-1] != '\0')
99 return -EINVAL;
100
101 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
102 if (priv == NULL)
103 return -ENOMEM;
104
105 priv->tginfo = info;
106 priv->oif = -1;
107 info->priv = priv;
108
109 mutex_lock(&priv_list_mutex);
110 list_add(&priv->list, &priv_list);
111 mutex_unlock(&priv_list_mutex);
112 } else
113 info->priv = NULL;
114
115 static_key_slow_inc(&xt_tee_enabled);
116 return 0;
117}
118
119static void tee_tg_destroy(const struct xt_tgdtor_param *par)
120{
121 struct xt_tee_tginfo *info = par->targinfo;
122
123 if (info->priv) {
124 mutex_lock(&priv_list_mutex);
125 list_del(&info->priv->list);
126 mutex_unlock(&priv_list_mutex);
127 kfree(info->priv);
128 }
129 static_key_slow_dec(&xt_tee_enabled);
130}
131
132static struct xt_target tee_tg_reg[] __read_mostly = {
133 {
134 .name = "TEE",
135 .revision = 1,
136 .family = NFPROTO_IPV4,
137 .target = tee_tg4,
138 .targetsize = sizeof(struct xt_tee_tginfo),
139 .usersize = offsetof(struct xt_tee_tginfo, priv),
140 .checkentry = tee_tg_check,
141 .destroy = tee_tg_destroy,
142 .me = THIS_MODULE,
143 },
144#if IS_ENABLED(CONFIG_IPV6)
145 {
146 .name = "TEE",
147 .revision = 1,
148 .family = NFPROTO_IPV6,
149 .target = tee_tg6,
150 .targetsize = sizeof(struct xt_tee_tginfo),
151 .usersize = offsetof(struct xt_tee_tginfo, priv),
152 .checkentry = tee_tg_check,
153 .destroy = tee_tg_destroy,
154 .me = THIS_MODULE,
155 },
156#endif
157};
158
159static struct notifier_block tee_netdev_notifier = {
160 .notifier_call = tee_netdev_event,
161};
162
163static int __init tee_tg_init(void)
164{
165 int ret;
166
167 ret = xt_register_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
168 if (ret)
169 return ret;
170 ret = register_netdevice_notifier(&tee_netdev_notifier);
171 if (ret) {
172 xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
173 return ret;
174 }
175
176 return 0;
177}
178
179static void __exit tee_tg_exit(void)
180{
181 unregister_netdevice_notifier(&tee_netdev_notifier);
182 xt_unregister_targets(tee_tg_reg, ARRAY_SIZE(tee_tg_reg));
183}
184
185module_init(tee_tg_init);
186module_exit(tee_tg_exit);
187MODULE_AUTHOR("Sebastian Claßen <sebastian.classen@freenet.ag>");
188MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
189MODULE_DESCRIPTION("Xtables: Reroute packet copy");
190MODULE_LICENSE("GPL");
191MODULE_ALIAS("ipt_TEE");
192MODULE_ALIAS("ip6t_TEE");
193
